The present invention relates to a rotor, a method for producing a rotor, an asynchronous machine and a vehicle. The present invention relates, in particular, to a rotor for an asynchronous machine, a method for manufacturing a rotor for an asynchronous machine, and an asynchronous machine, in particular for a drive of a vehicle, and a vehicle, in particular a passenger car and/or a hybrid vehicle.
Asynchronous machines are used in many technical applications, in particular when providing drive to vehicles and their components. Such machines are also referred to as three-phase asynchronous machines or three-phase induction machines. In such machines, a rotor and a stator interact with one another via rotational magnetic fields, wherein in the generator mode the rotor leads the stator rotational field, and in the motor mode the rotor lags the stator rotational field.
In passive asynchronous machines, the rotor is formed by a short-circuit rotor or cage rotor. Such a rotor is composed of a laminated core, in particular of an iron laminated core with grooves formed in it, wherein the laminations are electrically insulated from one another. Rods are usually introduced into the grooves in the laminated core during the production process and electrically short-circuited by means of short-circuit rings, which can be done by way of a casting process.
It is problematic that substitution of materials in order to improve the electrical conductance values, on the one hand, and increasing the mechanical stability, on the other, cannot be carried out with known production methods, or can only be carried out with considerable additional expenditure in terms of material and energy.
The invention is based on the object of specifying a rotor for an asynchronous machine, which rotor makes the design and the operation of an asynchronous machine more reliable, without increasing expenditure during production. In addition, the invention is based on the object of specifying a corresponding production method for a rotor, an asynchronous machine and a vehicle, and correspondingly developing said method.
The object on which the invention is based is achieved according to the invention with a rotor for an asynchronous machine, a method for manufacturing a rotor for an asynchronous machine, an asynchronous machine so produced, and a vehicle with the asynchronous machine, in accordance with embodiments of the invention.
According to one aspect of the present invention, a rotor is provided for an asynchronous machine, comprising a laminated core and a short-circuit cage (also known as a “squirrel” cage) which is at least partially integrated into the laminated core. The short-circuit cage is constructed with rods made with or from a first electrically conductive material and short-circuit rings made with or from a second electrically conductive material. At least one of the short-circuit rings is constructed with a support ring, and a respective support ring is constructed as a structure which is cast onto or into the respective short-circuit ring in a positively locking and/or materially joined fashion. As result of the fact that at least one of the short-circuit rings is constructed with a support ring as a structure which is cast on or in in a positively locking and/or materially joined fashion, a particularly close and mechanically stable relationship is manufactured between the short-circuit ring and the support ring. The support ring can also be easily integrated as a cast-in or cast-on structure during a production method for the short-circuit ring on the basis of a casting process No particular or newly added working steps such as bonding, pressing or the like are necessary.
A particularly high level of mechanical stabilization of the rotor according to the invention also arises if a respective support ring is constructed entirely or partially on the outer circumference of the respective short-circuit ring and/or is entirely or partially embedded in the respective short-circuit ring.
In another embodiment of the rotor according to the invention, the relationship between the short-circuit ring and the support which stabilizes the short-circuit ring is enhanced further by constructing a respective support ring on its surface with a contour, in particular with one or more recesses and/or with one or more projections for supporting the positive locking and/or the material join with the respective short-circuit ring.
With respect to the support ring, since the electrical properties of the short-circuit ring are, depending on the positioning in relation to the short-circuit ring, not significant, the possibility is provided of a more wide-ranging selection of materials, in particular with respect to stabilizing the short-circuit ring with respect to large centrifugal forces, in particular in the case of untrue running.
Therefore, according to an alternative embodiment of the rotor according to the invention, it is provided that a respective support ring is constructed with or from a material from a group of materials which comprises metallic materials, ceramic materials and composites, in particular with or from glass materials and/or carbon fiber materials.
Alternatively, a support ring can also be constructed with or from the same material as the respective short-circuit ring.
The stabilization of the short-circuit ring or rings in mechanical terms by the use of a cast-in or cast-on support ring also permits the use of material combinations with respect to the rods and/or the short-circuit rings, particularly taking into account the respective electrical conductivity and, if appropriate, without particular focus on the mechanical stability of the short-circuit ring because according to the invention the latter is stabilized mechanically by the cast-in or cast-on support ring.
It is therefore possible, in particular, that (i) the rods are constructed in or with a cast and/or joined structure, (ii) one or more of the short-circuit rings are constructed as end rings, (iii) the first material has a higher electrical conductivity than the second material, (iv) the second material has a greater mechanical strength and/or stability than the first material, (v) the first material and/or the second material is a material from the group which comprises aluminum, copper, silver and the combinations and alloys thereof, and/or (vi) the first material is or has copper and a copper alloy, and the second material is or has aluminum or an aluminum alloy.
According to another aspect of the present invention, a method for manufacturing a rotor for an asynchronous machine is provided.
Such an asynchronous machine is constructed with a laminated core and at least one short-circuit cage which is partially integrated into the laminated core. According to the invention, in the production method, the short-circuit cage is constructed with rods which are formed with or from a first electrically conductive material, and with short-circuit rings which are formed with or from a second electrically conductive material. At least one of the short-circuit rings is constructed with a support ring, wherein a respective support ring is cast on or into the respective short-circuit ring in a positively locking and/or materially joined fashion.
In one advantageous development of the production method according to the invention, in order to achieve a particularly high level of mechanical stability, a respective support ring is entirely or partially constructed on the outer circumference of the respective short-circuit ring and/or entirely or partially embedded in the respective short-circuit ring.
The mechanical integrity between the support ring and the supported short-circuit ring can be enhanced further if, according to another preferred embodiment of the production method according to the invention, a respective support ring is constructed on its surface with a contour, in particular with one or more recesses and/or with one or more projections for supporting the positive locking and/or the material join with the respective short-circuit ring.
Material aspects can also be taken into account in order to increase the stability of the structure to be manufactured. This can be done, for example, in that, according to one preferred embodiment of the production method, a respective support ring is constructed with or from a material from the group of materials which has metallic materials, alloys, ceramic materials and composites, in particular with or from glass materials and/or carbon fiber materials, and combinations thereof.
As an alternative, a support ring can also be constructed with or from the same material as the respective short-circuit ring.
According to further alternatives of the production method according to the invention, there may be provision that (i) the rods are constructed in or with a cast and/or joined structure, (ii) one or more of the short-circuit rings are embodied as end rings, (iii) a material with a higher electrical conductivity than the second material is used as the first material, (iv) a material with a higher mechanical strength and/or stability than the first material is used as the second material, (v) a material from the group which has aluminum, copper, silver and combinations and alloys thereof is used as the first material and/or as the second material and (vi) in particular, copper or a copper alloy is used as the first material, and aluminum or an aluminum alloy is used as the second material.
The method according to the invention is configured in a particularly economical way according to one advantageous development if a respective short-circuit ring is constructed by a casting process using a mold, and at the same time a support ring or a preform of the support ring of the short-circuit ring is previously positioned in the mold and therefore also cast on or in during the casting of the short-circuit ring.
The present invention also provides an asynchronous machine, in particular for the drive and/or as a generator of a vehicle. The asynchronous machine according to the invention has a rotor according to the invention and a stator.
In addition, the present invention provides a vehicle, in particular a passenger car, a battery-operated electric vehicle and/or a hybrid vehicle. The vehicle is equipped with an asynchronous machine which is constructed according to the invention and which is constructed as part of a drive and/or a generator of the vehicle.
The asynchronous machine in accordance with the invention may also be used in any other devices as a drive and/or as a generator component, e.g. in working machines or machine tools, in particular in a circular saw, in pumps, e.g. water pumps, in hydraulic generators and wind-powered generators, and the like.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.